The role of fine-needle aspiration cytology in the surgical management of thyroid cancer

Background: Diagnosis of thyroid malignancy relies on clinical assessment, imaging and fine-needle aspiration cytology 'FNAC' of thyroid nodules. The purpose of this study was to evaluate how effective synoptically reported FNAC is in clinical practice in diagnosing thyroid cancer. We also examined the effectiveness of using preoperative FNAC results to plan the type of operation for treating thyroid cancer. Method: A retrospective case series of all patients undergoing thyroid surgery from 1993 to 2008 was analysed. All data were collected prospectively and recorded in a dedicated endocrine surgery database. Data analysed included age, sex, preoperative FNAC result, type of surgery, final histology and complications. Cytology was reported based on a five-tiered classification system. Results: There were 1373 patients in total and 125 patients with a final diagnosis of thyroid cancer. Female to male ratio was 3:1. Cytology reported as 'malignant' was confirmed as thyroid cancer in 100% of the cases. Of the patients, 47% with 'suspicious' cytology report and 14% with 'follicular/indeterminate' cytology report had a final diagnosis of cancer. Thyroid cancer subtypes were 90 patients with papillary thyroid cancer 'PTC', 24 with follicular 'FTC', eight with medullary 'MTC' and two with anaplastic cancer. Cytology was suggestive of cancer in 89% of the patients with PTC > 10 mm, 75% with FTC and 88% with MTC. Transient hypocalcaemia was the commonest complication occurring in 7.2%. There were no cases of permanent hypoparathyroidism. Recurrent laryngeal nerve neuropraxia occurred in 2.4% with a permanent palsy occurring in 0.8%. There were three cancer-related deaths. Conclusions: Preoperative synoptically reported FNAC is effective when used in diagnosing and planning surgery for thyroid cancer.